1. Field of the Invention
This invention relates to missiles in which steerage can be maintained after propulsion is lost.
2. Description of the Prior Art
Guided missiles are, of course, well known. A typical guided missile is made up of a warhead, a rocket motor which propels the warhead and a guidance system. The guidance system is made up of a seeker which seeks out the target and various servomechanisms which receive signals from the seeker depending upon the relative positions of the target and missile and react, depending on what signals are received, to guide the missile ever closer to the target.
In a guided missile, positive physical control of the direction in which it flies, i.e., steerage, is typically achieved by means of aerodynamic surfaces or by controlling the direction of the propulsive gases relative to the missile. Consequently, once the propelling motor burns out steerage is lost when the missile velocity degrades below a certain point in the first case and immediately upon burnout in the second case. If the missile has not come within kill distance of the target prior to loss of steerage, it will merely coast on, out of control, and finally fall harmlessly to the ground. Since a typical missile is travelling at several times the speed of sound when burn-out occurs, a typical missile will obviously coast a long way before falling to the ground. It would, accordingly, be advantageous if positive control of the missile could be maintained after rocket motor burn-out in cases where the missile has no aerodynamic surfaces and after velocity degradation where a missile does have aerodynamic surfaces in order to make use of the existing energy of the missile. That is, if steerage could be maintained the missile could be brought to within kill distance of the target even after burn-out had occurred.